Skip to main content

Replies sorted oldest to newest

In short, an MTH TIU is not a power supply - it is a digital command interface.  The Track Interface Unit (TIU) is the brains behind the DCS system. Connected between the transformer and the track, the TIU receives signals from the DCS remote control and relays those signals to each train you are controlling via the rails. The type of signal relayed to the train depends on the operating mode at the time. If operating conventionally, the TIU will raise and lower track voltage to control engine speed. If operating in command mode, the TIU will send a digital signal to each train you are controlling via the track rails.

Pg 113 of the manual discusses operation of Conventional Locomotives using a DCS system with a TIU,

Pg 11 starts the section on wiring, including the use of classic transformers.

The manual itself:

https://mthtrains.com/sites/de...ction/20as14017i.pdf

As for differences, off the top of my head:

  • With a classic transformer, a pure sine wave signal is sent to the track. With command systems, most variable control is done electronically and therefore produces a modified sine wave to the track. This modified sine wave can cause some components to run warmer; This is seen as a benefit for smoke units. Note that this un-pure sine wave can be detrimental to some the operation of sensitive electrical components, notable some MTH PS1 locomotives are very picky in conventional mode.
  • With a classic transformer, the full voltage range can be directed to the track. Some of Lionel's transformers, this can approach be 24VAC. Common command systems such as MTH DCS is restricted to a voltage of ~18VAC.
  • Some classic transformers have a 5V boost to compensate for the additional electrical demands of the air whistle motor. The common command systems do not provide this boost.

I'm not disagreeing with cleaning brush dust and lubing as this coincides with increased voltage needs (cars too, clean those wheels oil any that need it (wipe oil on rust, brush, oil, wipe, repeat until clean, wipe well with an absorbant cloth. A little oil "darkness" is protection)

Some locos I have won't wake up until they have warmed up. It's nothing new to me. Warm ups were rituals for Gramps. The loco would sit until smoke got cooking, then it would get a good two or three laps alone on an 18x30 at LEAST before it pulled a load. 

I.e., yes I have to apply 100% of a 1033/15v 4a to wake up a few pre/postwar cast era locos.  Some cannot pull a load until they warm up. They also get run at full throttle most of the time. (same trains on a kw fly around, pull 25+ cars (I only have so much room) and can jump rails)

However, some engines do need more voltage when they wear too. Look that the axles dont wobble fwd/back; shift away from the gears (needs bushings?) Also note how the gears ride on their shafts. Worn will tilt off plane once side thrusts start. Eventually bad bushings/gears can bind out of sequence/lock up, esp. 6 driver PW. (gearposts can usually live a longer life with prudent gear changes)

I presume you are operating these locos in conventional mode, using the DCS remote, and through the variable channels of your TIU.

Disclaimer: It's been a very long time...  My TIU is one of the very first models, and I never upgraded the operating system beyond 3.xx.  But if I recall correctly, when using the variable channels, the indicated voltage on the remote's LCD display wasn't accurate.

All bricks are not created equal.  Which one(s) are you using?  Do you have a traditional transformer to compare against? 

The most important test:  if you put a volt meter on the rails when the train is running, what does it read?  How does that compare to what the remote is telling you?  Please try this test and post back with your results.

It's very possible that your locos are drawing excess voltage due to wear, or lack of maintenance.  But they could also be operating normally.  We can't tell unless we know the actual voltage on the rails.  Measuring it during operation with a meter is the best way to find out.

Last edited by Ted S

First off, when you dial up 14 volts on the DCS remote for a variable track, it's not necessarily really 14 volts.  The DCS remote assumes 22 volts input and divides it's speed steps up with that assumption.  It changes voltage in 1/2 volt steps, so there are 44 steps.  So, that 14 volts would equate to step 28.  Now, let's assume you are putting 17.5 volts into the TIU instead of their assumed 22 volts.  That means you're only putting 80% of the voltage that the DCS is assuming for track voltage.  The indicated 14 volts on the DCS remote is really putting 11.14 volts on the track.

Next, consider the vagaries of the chopped waveform generated by the TIU in the mix, and it's difficult to know what amount of energy you're really bringing to the table using the TIU to regulate the voltage.

Whether you're using two bricks and a TIU or a regular transformer to supply power to the track, it shouldn't make a difference how the voltage gets there - after all, 14v at the track is 14v. 

There may be differences attributable to internal voltage loss in each system and degree of accuracy, different wave forms and insuring the TIU is getting a full 18v to start with, but once those differences are accounted for and each system adjusted to insure 14v to the track, it shouldn't make a difference to your engine whether the 14v is coming from one or the other. 

Assuming you have the Lionel transformer to test with, I would first dial up 14v to the track through the TIU and measure the track voltage with no load (no train on track) and then with a load and then repeat using the transformer and compare the results. 

 

Last edited by Richie C.

Even your digital voltmeter cannot read the non sinusoidal wave form correctly, so your 9 VAC from your TIU, is probably not really equal to 9 VAC of sinusoidal waveform energy, out of an old ZW......so just oil your trains and have fun running the old stuff with of the DCS...I've been doing that for years, but the old stuff needs a lot more lube attention than any of the newer stuff.  BTW, I'm an Electrical Engineer, that works daily with Variable Speed AC and DC drives....with and without encoder feedback. Also note the DCS doesn't read voltage, as noted above by John.

@radar493 I would really like to help you.  Which brick(s) are you using: model number, watts, etc.  What's the indicated voltage on the remote when you are measuring 9 volts on the rails?  Also: which loco(s) are you running with this setup?  About how long is your loop, what kind of track?  Any grade (incline)?  These things DO matter!

If you don't want to type all this out, please take some photos or a video.

With all that being said, I totally agree with Chuck.  Personally I don't like running postwar trains with the TIU in variable mode.

@Ted S posted:

@radar493 I would really like to help you.  Which brick(s) are you using: model number, watts, etc.  What's the indicated voltage on the remote when you are measuring 9 volts on the rails?  Also: which loco(s) are you running with this setup?  About how long is your loop, what kind of track?  Any grade (incline)?  These things DO matter!

If you don't want to type all this out, please take some photos or a video.

With all that being said, I totally agree with Chuck.  Personally I don't like running postwar trains with the TIU in variable mode.

Thanks. I have one Lionel ph1 powerhouse brick powering variable two input to TIU. I am running #2035 w tender and five light cars. Track is all Gargraves loop is 054 (5x10') no switches simple loop of track. Remote shows 8v. TIU variable output shows 7.5v. Track agrees with TIU . Train will only move with about 10 v output. So my original question was is 10 volts reasonable or should my #2035 with the above consist run on less voltage and would a Lionel small transformer run on less. I do also operate command engines so if I got another transformer for my post-war engines I would need to switch between the two. No big problem.

Ok... The 2035 is a fairly "heavy-duty" loco with smoke and magne-traction.  When you factor in a heavy whistle tender and 5 lighted cars, that's a lot of drag!  So 10 volts isn't excessive to get the train moving, especially if your loco might need cleaning or lubrication.  Is the loco spry and responsive by itself, without the train?

As you increase the thumbwheel on the DCS remote, the voltage on the screen will probably begin to read higher than what's actually going to the track.  Don't be too concerned about the digital readout, it's a proportional approximation.  MTH's bricks put out 22 volts so at 18V the Lionel Powerhouse PH-1 is down a little from that.  It should still be adequate, but going through the TIU, not all of that voltage will be available at the rails.  If in doubt check the voltage on the rails with a meter. 

Some other thoughts:  Look over the tender and your passenger consist.  Spin each wheel with your finger.  If necessary put one! (1) drop of oil on each bearing surface where the axle goes into the wheel, and where the axle meets the truck.  You can do this on the pickup rollers too, but be sure to wipe off any excess. 

If the track is brand-new, running your train will burnish its surface and friction may be reduced so it might run faster or more responsive.  Make sure the track is plugged together tightly for good electrical conduction.  Also, that wheels and rollers don't "snag" on the gaps between sections.  This can cause the train to stall at very slow speeds.

If you really want more speed and power to spare, you would need a 22-volt MTH brick, a 180-watt Powerhouse, or a top-tier transformer like a ZW, ZW-L, or Z4000.  But if your passenger car windows are glowing white hot, you might be applying too many volts and your loco is probably in need of maintenance.  Hope this helps!

Add Reply

Post
OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
330-757-3020

www.ogaugerr.com
×
×
×
×
Link copied to your clipboard.
×
×